Recent changes in the construction industry have led to an increased use by builders of prefabricated building components manufactured offsite. Despite its many benefits, however, builders have not fully embraced prefabricated building components using alternatives to conventional wood framing. For example, even though steel framing has many advantages over conventional wood framing, there has been reluctance in residential construction, and some types of commercial construction, to use components made from steel, rather than wood, due in part to the belief that steel is more costly. Dimensioned lumber prices, however, are highly volatile. An insulated steel frame panel system that is cost competitive to conventional wood framing, incorporates recognized and readily available components, and that is easily and quickly assembled and installed, has many advantages over conventional wood framing and would be embraced by the building industry and building owners.
A number of panels have been designed that incorporate foam insulation for improved thermal performance. These panels, however, often incorporate nonstandard light gage steel framing members (e.g., U.S. application Ser. No. 11/825,562 to Miller, U.S. application Ser. No. 11/282,351 to Onken et al., U.S. patent application Ser. No. 11/068,608, to Rue, U.S. Patent Application Publication No. 2011/0047912 to Armijo, U.S. application Ser. No. 11/361,189 to Bowman) and often require the manufacture of the panel within a mold, (e.g., Rue and U.S. Pat. No. 5,399,462, to McKinney). Others envision the insertion of framing members in larger channels or voids in the foam or that require an adhesive to lubricate the stud insertion and/or to adhere the stud in the foam (e.g., Miller).
New building codes recognize the importance of eliminating thermal bridging. Newer codes require a layer of continuous insulation unless a wall assembly can demonstrate an acceptable level of thermal performance without it. The layer of continuous insulation creates new building challenges, among which are fastening and exterior finish details, moisture control, and the ratio of rigid continuous insulation to batt or loose fill insulation in the wall cavity.
Since a structural panel by nature generally requires support on both the exterior and interior of the panel, some panelized systems use nonstandard steel framing members in order to create sufficient strength in the steel member to avoid multiple connecting bridges through the panel. For example, the nonstandard framing member in Miller has additional bends in the steel framing member to provide additional strength. While such efforts can help avoid thermal bridging, the use of a nonstandard framing member generally requires extensive and expensive testing to demonstrate compliance with building codes, including structural analyses and fire testing under superimposed loads if the foam is intended to serve any structural support purpose. A panelized system that minimizes thermal bridging but which emphasizes the use of conventional steel framing members will be more economical to manufacture and will ensure more rapid acceptance by the building industry.
Other building panel systems that incorporate nonstandard light gage steel members and foam insulation have addressed thermal bridging in various ways, but generally are designed in ways that will also require substantial structural (and other) testing to gain acceptance by the building industry and building code officials. Also, they generally require a manufacturing process that is complex and not economical. These factors have generally limited the commercial practicability of these approaches.
Fireblocking is used to prevent the free passage of flame to other areas of the building through concealed spaces. To meet fire/building code specifications and improve fire safety, a panelized system that is used in balloon framing or as a curtain wall in certain other multistory construction will require fireblocking as part of the wall assembly to meet flammability requirements, as well as lateral and vertical flame spread in some building applications.
In traditional construction, cable/utility runs in walls are not well integrated with the framing. Groupings of tubing (such as PEX plumbing), electrical, data, voice, and audio wiring are often commingled or loose in a common area within a cable/utility run wall cavity. These cables, wires and tubing are generally secured in wood framing using secondary means (such as staples, nails, clips, and tacks), which may puncture the cables, wires and/or tubing upon coupling to the wall. In steel framing, similar attachment means are used such as tie wire, clips, hangars, and mechanical fasteners, each of which may also puncture or abrade the cables, wires, and/or tubing. Moreover, the channel/utility run often results in an opening for thermal, sound, and vibration inefficiencies. In a solid panel system, planning for the placement of cable and utility run is an important feature.
Conventional steel framing members in EPS panels may have a top track and a bottom track. The bottom track may be attachable to a floor, and the top track may be attachable to a ceiling. However, these tracks may present an opportunity for sound and/or vibration to travel from one side of the wall to the other, as well as create a thermal bridge from one side of the panel to the other. Mechanical air handling equipment and elevators in buildings cause harmonic vibrations. These vibrations can cause mechanical connections to loosen, structural and nonstructural welds to weaken, and nuisance noise production through the structure.